Center for Remote Sensing, Inc.

Other

Suman Ganguly

Yoonjae Lee

Raj Mittra

Andrew Brown

Aleksandar Jovancevic

An antenna having multiple antenna elements of unequal lengths, form in a conical shape. The longest antenna element has a trap in a specific location of the antenna element. Multiple traps can be used for extended coverage depending upon the frequency band. The antenna elements are connected together through a transversal-wire ring and a feed transmission line is attached to it. The antenna occupies minimal footprint in the horizontal direction and maintains a low VSWR and a uniform beam pattern over a wide frequency band, more than 1:20. The antenna has a constant radiation pattern over a 1:6 bandwidth and the pattern bandwidth may be increased using more antenna elements and traps. The elevation and azimuth patterns show a consistent characteristic from 100 MHz to 600 MHz.

Compact broadband antenna with constant radiation pattern

Calibrating a receiver for a satellite positioning system. At preset intervals, a plurality of calibration signals are generated and applied to the receiver. The plurality of calibration signals correspond to a plurality of satellite signals, respectively, from the satellite positioning system. A relative time-delay bias from a delay estimation algorithm within the receiver. The time-delay bias is stored, preferably with the receiver. The receiver receives the plurality of satellite signals from the satellite positioning system. The plurality of satellite signals are processed with the time-delay bias. The processing reduces effects from the satellite receiver and improving estimate of the differential delay and total electron content (TEC).

GPS receiver with calibrator

A multifrequency antenna comprising a stack of nonconductive substantially planar substrates, with a conductive layer disposed on each substrate surface. A first substrate includes transmission lines disposed on a rear surface and a conducting layer on the other surface. A second substrate is stacked on the first substrate. A conducting layer is disposed on one side of the second substrate surface. Conducting layers disposed on first and second substrates include a plurality of slotted openings arrayed about an antenna axis. A third substrate stacked on the second substrate includes a conducting layer top. A lossy dielectric-magnetic material encloses sides and rear of the multifrequency antenna, to prevent electromagnetic energy penetration through the enclosure. An edge diffraction suppresser reflector is attached in the rear surface of the multifrequency antenna, and has two or more essentially circular, conducting plates and a multitude of conducting cylinders along the axis of the multifrequency antenna.

Multifrequency antenna with reduced rear radiation and reception

A passive system for detecting the position and trajectory of a moving body, moving in the air, on the ocean or below the ocean. This apparatus operates by detecting perturbations in the earth's magnetic field responsive to the movement of a body through the field. At least two spaced magnetometers are provided to detect the perturbations of the earth's magnetic field, whereas, the system works more efficiently with an array of sensors. These two sensors are used to filter out the ambient noise. The outputs of these sensors are digitized and inverted through correlation procedures and an output is provided on a display.

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Falls Church, VA, United States of America

Suman Ganguly